Changing Video/Output(#3) will change it for both streaming and recording. The other 2 will rescale the output resolution(Downscale Resolution) you have set up in Video/Output, they can be ignored in most use cases.
If you want to record and stream at 2 different resolutions, that is when they come into play.
Set your scene size to be the same as your monitors native resolution, set your output(downscale) resolution to be what you want to record at, set your FPS. If you are not downscaling from native resolution don't worry about the filter. If you are downscaling, Lanczos is good in most cases but in some cases it is not the best choice, despite popular opinion.